In the fields of solar batteries, light emitting devices and touch panels or the like, a metal oxide film having transparency is formed on a substrate. As techniques for forming a ZnO film as the metal oxide film on the substrate, those disclosed in Patent Document 1 and Non-Patent Document 1 conventionally exist.
In the technique according to Patent Document 1, a film is formed by an ion plating method using a ZnO sintered body containing 0.5 to 16% of Ga2O3. In the technique according to Non-Patent Document 1, a ZnO film is formed on a substrate by a pulse laser accumulation method of irradiating a ZnO sintered body with KrF laser.
Patent Document 1: Japanese Patent Application Laid-Open No. 2007-109406
Non-Patent Document 1: The Journal of the Vacuum Society of Japan Vol. 50 (2007), No. 2, 114-117